Like the wide-eyed humans who mistakenly trust their benevolent alien overlords in Arthur C. Clarke’s science-fiction classic, Linux users the world over are beginning to awaken to the reality that their malware- free utopian childhood is rapidly coming to an end.

A startling increase in malware, ransomware and malicious code targeting Linux systems of all shapes and sizes since 2015 means the days of believing it’s “just a Windows thing” are over. One study found that Linux malware now accounts for more than 35% of all malware, and anyone not taking Linux security threats seriously can face real—and expensive—problems.